Channel state information (CSI) is required at the transmitter for beamforming, user pairing, and power allocation, and at the receiver for SIC and symbol decoding. Imperfect channel estimation causes power allocation ambiguity which reduces the NOMA sum rate. It is essential to investigate the effect of channel mismatch caused by THz propagation characteristics such as beam squint and spherical wave propagation. Due to the large number of antennas at both the transmitter and receiver, computationally efficient channel estimation solutions are crucial [1]}.
